Prepare the ziti as directed. Reserve 1/4 cup of the pasta water before draining the pasta.
While the pasta is cooking, slit and remove the casings from the sausage links. Mash up the meat and place on a frying pan with a drizzle of olive oil.
Brown the sausage meat, being careful to stir and turn the meat to make sure it is no longer pink inside. While meat is cooking, season with salt and pepper (to taste). Add 1/2 tsp of the cayenne and 1 tbsp of the crushed red pepper, too.
When the meat is almost browned, add the minced garlic. Stir for about 1 minute and then turn off the heat so the garlic doesn't burn.
When the pasta is cooked, drain and set aside in a colander. In the same pasta pot (with the reserved water), add the ricotta, half of the spaghetti sauce and half of the parmesan cheese. Stir until creamy.
Add the remaining cayenne and crushed red pepper and italian seasoning to the sauce mixture.
Add the meat to the ricotta/sauce mixture.
Add the pasta into the sauce/meat mixture.
Grease a casserole pan lightly with olive oil.
Place an even layer of the pasta mixture, only using half of it.
Place half of the mozzarella and half of the remainder spaghetti sauce on top of the pasta layer. Sprinkle with some parmesan, if desired.
Place the second half of the pasta mixture on top of the first. Put the rest of the mozarella, spaghetti sauce and parmesan cheese on top.
Sprinkle the top with the remaining crushed red pepper.
Cover casserole pan with foil and bake for 35-40 minutes at 350 degrees. Cheese should be melted and sauce should be a bit bubbly.